Multiple passes from 3D CAM software

[mickelsen]

Hello all,
I have a desktop CNC router and I have been doing just fine with 2D projects. I use Mach3 and Cut2D. Now I would like to move up to 3D routing and milling. I've been looking at free or low cost 3D cam packages ('cause I got no money). These include CamBam, CNC_Toolkit, FreeMill, even Cut3D, and others. I know that I'm just a novice so maybe I'm not understanding something, but they all seem to have very confusing toolpath displays and, no matter how deep a cut needs to be, they all generate just one pass for it. Cut2D automatically generates multiple incremental passes for it's cuts, but none of the 3D packages seem to do this.
Am I missing something? It feels like there is something fundamentally different between 3D milling and 2D milling, and I didn't expect that.
Is there something I could read that would help me make the transition to 3D cutting? Or maybe a thread here on this site?
Any help would be appreciated.
Mark

[ger21]

FreeMill only gives you one pass, cause it's free. . With Cut3D, first you do a roughing toolpath, which will give you the option of cutting in multiple passes. You may need to set the max depth per pass by editing the tool. After the roughing, you do a finishing toolpath. Finishing will always be a single pass.

Haven't used CamBam or Toolkit, but most 3D CAM packages operate the same way.

Rough toolpath with multiple passes, followed by finishing toolpath, single pass.